Filtration devices for the treatment of blood are known. For example, U.S. Pat. No. 4,498,990 discloses a cellular blood component/plasma separation device comprising two hollow fiber bundles situated coaxially to each other in a housing having blood inlet and outlet ports, a filtrate outlet port, and a replacement liquid port for supplying plasma makeup of undisclosed composition (probably proteins and sugars) to the treated blood prior to its reintroduction to the donor. U.S. Pat. No. 4,668,399 discloses a single-pass nonwashing plasmapheresis module and process for use on whole blood (having a Hematocrit of about 35-45) having short hollow fibers with an effective length to lumen diameter ratio of not greater than 300 in a steady state flow mode and not greater than about 540 in a pulsed flow mode. U.S. Pat. No. 31,688 (Re.) also discloses a nonwashing single pass plasmapheresis nonhollow fiber membrane device. U.S. Pat. No. 4,631,050 discloses a batch autotransfusion system that, following macrofiltration of a patient's whole blood and prior to a planar membrane separation of the plasma and cellular components, permits batch washing of the blood by mechanical agitation with saline solution. U.S. Pat. No. 4,565,626 discloses a device for removing toxins from blood that contacts the blood for a period of time with adsorbent material packed between hollow fibers, then withdraws the blood from the adsorbent; saline solution is used as a pressure-transmitting medium. Finally, U.S. Pat. No. 4,038,190 discloses a fluid fractionation apparatus having two fiber bundles in series with an externally-supplied fluid inlet port that permits a fluid to be supplied to the outside (as opposed to the lumen side) of the hollow fibers.
However, none of the foregoing devices addresses the need for an efficient combination blood component washing, concentration and separation device capable of performing such operations in a continuous mode, and capable of operating on both whole and diluted blood, the latter being encountered in surgical cavities as a result of the use during surgery of saline wash to cleanse the surgical field.
The present invention meets such a need, thus providing a significant advance in the art of blood filtration and treatment, as well as providing other advantages and efficiencies which will become apparent from the detailed description which follows.